A tandem macro-dimerization reaction via a Cu(I) catalyzed azide/alkyne cycloaddition reaction ha... more A tandem macro-dimerization reaction via a Cu(I) catalyzed azide/alkyne cycloaddition reaction has been employed to construct triazole/urea based peptidomimetic macrocycles considered as pseudocyclo-β-peptides. Introduction of one particular chirality in the peptide backbone can alter the conformation as well as nature of self-assembly from cyclic D-,L-,α-peptide to cyclo-β-peptide. One of them (16a) forms antiparallel dimers while the other (16b) undergoes higher order aggregation to form a nanorod structure.
A convenient method for the synthesis of 5- to 8-membered benzoheterocycles is achieved by 1,3-di... more A convenient method for the synthesis of 5- to 8-membered benzoheterocycles is achieved by 1,3-dipolar cycloaddition of o-iodophenyl-substituted azides with a variety of acetylenic substrates followed by cyclization of the resulting triazoles.
Carbohydrates U 0500 A Simple One-Pot Entry to Cyclic Ethers of Varied Ring Sizes from Diols via ... more Carbohydrates U 0500 A Simple One-Pot Entry to Cyclic Ethers of Varied Ring Sizes from Diols via Phosphonium Ion Induced Iodination and Base Catalyzed Williamson Etherification.-Optimized conditions allow the synthesis of cyclic ethers of varied ring size, present in natural products, from carbohydrate-derived diols.-(ROY, B. G.; ROY, A.;
Triazole derivatives R 0280 Palladium-Copper Catalyzed Heteroannulation of Acetylenic Compounds: ... more Triazole derivatives R 0280 Palladium-Copper Catalyzed Heteroannulation of Acetylenic Compounds: An Expeditious Synthesis of Isoindoline Fused with Triazoles.-The biologically significant heterocycles can be successfully prepared from ortho-iodobenzyl azide and terminal alkynes under optimized conditions A).-(CHOWDHURY*, C.; MANDAL,
This paper is published electronically. It meets the data-validation criteria for publication in ... more This paper is published electronically. It meets the data-validation criteria for publication in Acta Crystallographica Section C. The submission has been checked by a Section C Co-editor though the text in the "Comments" section is the responsibility of the authors. Acta Cryst. (2000). C56, e60-e61 Kinkini Bhattacharyya et al.¯C 34 H 52 O 4 electronic papers e60 Kinkini Bhattacharyya et al. C 34 H 52 O 4 Acta Cryst. (2000). C56, e60±e61 Oleana-12(13),15(16)-diene-3a,28diyl diacetate
New bromotyrosine derived secondary metabolites have been isolated from the marine sponge Psammap... more New bromotyrosine derived secondary metabolites have been isolated from the marine sponge Psammaplysilla purpurea, and the structures assigned on the basis of spectroscopic analyses of their acetates la' and lb'.
A new triterpene, 3β-hydroxy-26-nor-9,19-cyclolanost-23-en-25-one was isolated from the leaves of... more A new triterpene, 3β-hydroxy-26-nor-9,19-cyclolanost-23-en-25-one was isolated from the leaves of Garcinia mangostana and its structure elucidated by 1 H NMR and mass spectral studies. ... Keywords: Garcinia mangostana; Guttifereae; leaves; 3β-hydroxy-26-nor-9,19-...
Benzopyrans. Part 38. Reactions of 4-Oxo-4H-1-benzopyran-3carbaldehyde,-3-carbonitrile and-3-carb... more Benzopyrans. Part 38. Reactions of 4-Oxo-4H-1-benzopyran-3carbaldehyde,-3-carbonitrile and-3-carboxylate with Chloroacetone and a Note on the Stereochemistry of Benzo[b]cyclopropa[e]pyrans.-Treatment of the benzopyrans (I) with chloroacetone leads to the fused cyclopropanes (III) in the presence of K 2 CO 3 /KI. In the presence of Brockman neutral alumina the furocoumarin (IV) or the benzopyranones (V) and (VI) are obtained. The carbaldehyde (VII) gives the benzofuran (VIII) or the benzopyranone (IX) depending on the above conditions.-(GHOSH, CHANDRA
A tandem macro-dimerization reaction via a Cu(I) catalyzed azide/alkyne cycloaddition reaction ha... more A tandem macro-dimerization reaction via a Cu(I) catalyzed azide/alkyne cycloaddition reaction has been employed to construct triazole/urea based peptidomimetic macrocycles considered as pseudocyclo-β-peptides. Introduction of one particular chirality in the peptide backbone can alter the conformation as well as nature of self-assembly from cyclic D-,L-,α-peptide to cyclo-β-peptide. One of them (16a) forms antiparallel dimers while the other (16b) undergoes higher order aggregation to form a nanorod structure.
A convenient method for the synthesis of 5- to 8-membered benzoheterocycles is achieved by 1,3-di... more A convenient method for the synthesis of 5- to 8-membered benzoheterocycles is achieved by 1,3-dipolar cycloaddition of o-iodophenyl-substituted azides with a variety of acetylenic substrates followed by cyclization of the resulting triazoles.
Carbohydrates U 0500 A Simple One-Pot Entry to Cyclic Ethers of Varied Ring Sizes from Diols via ... more Carbohydrates U 0500 A Simple One-Pot Entry to Cyclic Ethers of Varied Ring Sizes from Diols via Phosphonium Ion Induced Iodination and Base Catalyzed Williamson Etherification.-Optimized conditions allow the synthesis of cyclic ethers of varied ring size, present in natural products, from carbohydrate-derived diols.-(ROY, B. G.; ROY, A.;
Triazole derivatives R 0280 Palladium-Copper Catalyzed Heteroannulation of Acetylenic Compounds: ... more Triazole derivatives R 0280 Palladium-Copper Catalyzed Heteroannulation of Acetylenic Compounds: An Expeditious Synthesis of Isoindoline Fused with Triazoles.-The biologically significant heterocycles can be successfully prepared from ortho-iodobenzyl azide and terminal alkynes under optimized conditions A).-(CHOWDHURY*, C.; MANDAL,
This paper is published electronically. It meets the data-validation criteria for publication in ... more This paper is published electronically. It meets the data-validation criteria for publication in Acta Crystallographica Section C. The submission has been checked by a Section C Co-editor though the text in the "Comments" section is the responsibility of the authors. Acta Cryst. (2000). C56, e60-e61 Kinkini Bhattacharyya et al.¯C 34 H 52 O 4 electronic papers e60 Kinkini Bhattacharyya et al. C 34 H 52 O 4 Acta Cryst. (2000). C56, e60±e61 Oleana-12(13),15(16)-diene-3a,28diyl diacetate
New bromotyrosine derived secondary metabolites have been isolated from the marine sponge Psammap... more New bromotyrosine derived secondary metabolites have been isolated from the marine sponge Psammaplysilla purpurea, and the structures assigned on the basis of spectroscopic analyses of their acetates la' and lb'.
A new triterpene, 3β-hydroxy-26-nor-9,19-cyclolanost-23-en-25-one was isolated from the leaves of... more A new triterpene, 3β-hydroxy-26-nor-9,19-cyclolanost-23-en-25-one was isolated from the leaves of Garcinia mangostana and its structure elucidated by 1 H NMR and mass spectral studies. ... Keywords: Garcinia mangostana; Guttifereae; leaves; 3β-hydroxy-26-nor-9,19-...
Benzopyrans. Part 38. Reactions of 4-Oxo-4H-1-benzopyran-3carbaldehyde,-3-carbonitrile and-3-carb... more Benzopyrans. Part 38. Reactions of 4-Oxo-4H-1-benzopyran-3carbaldehyde,-3-carbonitrile and-3-carboxylate with Chloroacetone and a Note on the Stereochemistry of Benzo[b]cyclopropa[e]pyrans.-Treatment of the benzopyrans (I) with chloroacetone leads to the fused cyclopropanes (III) in the presence of K 2 CO 3 /KI. In the presence of Brockman neutral alumina the furocoumarin (IV) or the benzopyranones (V) and (VI) are obtained. The carbaldehyde (VII) gives the benzofuran (VIII) or the benzopyranone (IX) depending on the above conditions.-(GHOSH, CHANDRA
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